.centertext {
    text-align: center; /*让div内部文字居中*/
    margin: auto;
    position: absolute;
    min-width: 800px;
    height: 300px;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}

.center {
    /*text-align: center; !*让div内部文字居中*!*/
    margin: auto;
    position: absolute;
    min-width: 800px;
    height: 300px;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
}